Abstract:Recently, the ultrafine entanglement witness was introduced in [F. Shahandeh, M. Ringbauer, J.C. Loredo, and T.C. Ralph, Phys. Rev. Lett. 118, 110502 (2017)], which can seamlessly and easily improve any standard entanglement witness. In this paper, by the combining the constraint and the test operators, we rotate the hyperplane determined by the test operator and improve further the original ultrafine entanglement witness.
We present a series of new ultrafine entanglement witnesses, which
can detect entangled states that the original ultrafine entanglement witnesses cannot detect.